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1980 MGB - Recommended gauge size for battery cables

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1980 MGB - Recommended gauge size for battery cables
#1
RPittenger Richard Pittenger
Troy, OH, USA   USA
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1980 MG MGB
Forum Friends,

I'm working on a project to add a battery disconnect to the car. I'll probably need at least one or maybe two new cables of different lengths than I now have. Also, I'm thinking that the cables now in the car are larger gauge (and stiffer) than needed. Can you suggest what gauge size wire is needed?

As always, thanks.
Richard

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Re: 1980 MGB - Recommended gauge size for battery cables
#2
ingoldsb Avatar
ingoldsb Silver Member Terry Ingoldsby
Calgary, AB, Canada   CAN
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1971 MG MGB
The gauge depends partly on the distance. Since the positive cable goes all the way to the front of the car the resistance adds up. For the long run I'd say a #2 gauge. For a short run (say from the battery to the disconnect switch) 4 gauge is probably sufficient. I would switch to 2 gauge from the switch to the solenoid, but you could probably get by with 4 gauge. If you have a modern starter which draws less current then 4 gauge is more acceptable.


Terry Ingoldsby
terry.ingoldsby@DCExperts.com

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Re: 1980 MGB - Recommended gauge size for battery cables
#3
red68mgb Avatar
red68mgb Silver Member Jim Milavec
Murrells Inlet, SC, USA   USA
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1968 MG MGB "Redginald"
I wasn't able to find any locally, but I was fortunate to find this supplier...

https://www.batterycablesusa.com/

Pick your gauge, color, length, ends, etc. all at a decent price and quick ship.


I'd rather wear out than rust out.

"If everyone is thinking alike, then somebody isn't thinking." General George Smith Patton

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Re: 1980 MGB - Recommended gauge size for battery cables
#4
OldDuffer Avatar
OldDuffer Silver Member John S
Eugene, OR, USA   USA
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1970 MG MGB "Ella B (totaled And Parted)"
1971 MG MGB GT "Ashley"
1979 MG MGB "Mae B *SOLD*"
I had a 4 ga cable made up at the local Interstate Battery store. Got rid of the old black, stiff cable and fit the new red one in its place. Not fun threading it through all of the rubber blocks that were covered it years of grime but worth it in the end.


I was addicted to the hokey pokey but I turned myself around.

prop-a-gan-da: When a British person takes a close look at something

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about 2 weeks and 6 days later...
Re: 1980 MGB - Recommended gauge size for battery cables
#5
wcalcutt William Calcutt
Clio, MI, USA   USA
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1970 MG MGB
1976 MG Midget 1500
1980 MG MGB Limited Edition (LE)
I just installed a new starter on my '80 B. The cable just barely reached the lug on the starter. How long was the cable you had made up?

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Re: 1980 MGB - Recommended gauge size for battery cables
#6
RPittenger Richard Pittenger
Troy, OH, USA   USA
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1980 MG MGB
William,

Sorry but I ended up not needing new battery cables as, for my battery disconnect switch, I went with an electronic unit having remote controls and mounted directly to the negative post of the battery completely within the battery compartment. Therefore, I didn't need to replace the battery cables, drill holes in the car, etc. So far, I've been very happy with that setup.

Regards,
Richard

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Re: 1980 MGB - Recommended gauge size for battery cables
#7
Bob Allen Avatar
Bob Allen Gold Member
Houston, TX, USA   USA
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1978 MG MGB
This is what I went with when I added a battery shut off and extended terminals.
Seems fine and the cables don’t get warm when in use.

https://a.co/d/7zFXdjk

Was plenty to do every thing I needed plus replaced the line to the starter.

Shut off switch. https://a.co/d/9ZMDa5I

Remote terminals. https://a.co/d/9ommqto


1978 MGB
When diagnosing issues related to running and stalling, always check to see if you have gas in the tank first.

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Re: 1980 MGB - Recommended gauge size for battery cables
#8
LENZ Avatar
LENZ Jim B
Leominster, MA, USA   USA
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1970 MG MGB GT
1974 MG MGB GT "White Lightning"
company name..?

In reply to # 4796594 by RPittenger William,

Sorry but I ended up not needing new battery cables as, for my battery disconnect switch, I went with an electronic unit having remote controls and mounted directly to the negative post of the battery completely within the battery compartment. Therefore, I didn't need to replace the battery cables, drill holes in the car, etc. So far, I've been very happy with that setup.

Regards,
Richard

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Re: 1980 MGB - Recommended gauge size for battery cables
#9
MGBGM1977 Avatar
MGBGM1977 Anthony Piper
Heaven in the woods, FL, USA   USA
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1974 MG MGB
1977 MG MGB V6 Conversion
I made my own cables with 4 gauge welding wire and premade copper ring terminals. My ground goes straight to the engine block and positive goes to a terminal post in the engine compartment.


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Re: 1980 MGB - Recommended gauge size for battery cables
#10
Bob Allen Avatar
Bob Allen Gold Member
Houston, TX, USA   USA
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1978 MG MGB
Grounding straight to the engine is fine as long as you still have the engine ground strap and trans straps in place, otherwise the body isn’t grounded and most of the components ground to the body.
I am sure you are aware of this, but wanted to mention it for some of the less knowledgeable.

In reply to # 4796696 by MGBGM1977 I made my own cables with 4 gauge welding wire and premade copper ring terminals. My ground goes straight to the engine block and positive goes to a terminal post in the engine compartment.


1978 MGB
When diagnosing issues related to running and stalling, always check to see if you have gas in the tank first.

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Re: 1980 MGB - Recommended gauge size for battery cables
#11
MGBGM1977 Avatar
MGBGM1977 Anthony Piper
Heaven in the woods, FL, USA   USA
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1974 MG MGB
1977 MG MGB V6 Conversion
Well of course I still have the original grounding straps. It only makes sense to take the ground cable as close to the most amp hungry item in the car that is the starter. Don't know why MG didn't do that in the first place. All other car manufacturers seem to do that.
In reply to # 4796959 by Bob Allen Grounding straight to the engine is fine as long as you still have the engine ground strap and trans straps in place, otherwise the body isn’t grounded and most of the components ground to the body.
I am sure you are aware of this, but wanted to mention it for some of the less knowledgeable.

In reply to # 4796696 by MGBGM1977 I made my own cables with 4 gauge welding wire and premade copper ring terminals. My ground goes straight to the engine block and positive goes to a terminal post in the engine compartment.

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Re: 1980 MGB - Recommended gauge size for battery cables
#12
ingoldsb Avatar
ingoldsb Silver Member Terry Ingoldsby
Calgary, AB, Canada   CAN
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1971 MG MGB
Quote: All other car manufacturers seem to do that.

Most other car manufacturers place the battery near the engine - so the ground cable is quite short. In the case of the MGB it would mean another 6 or 7 foot run of thick copper wire. Thick copper wire is expensive - hence the decision.


Terry Ingoldsby
terry.ingoldsby@DCExperts.com

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Re: 1980 MGB - Recommended gauge size for battery cables
#13
Bob Allen Avatar
Bob Allen Gold Member
Houston, TX, USA   USA
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1978 MG MGB
It wouldn’t need to be much longer than the positive cable that runs to the starter. You could connect it to one of the bolts on the bel housing.

In reply to # 4797367 by ingoldsb
Quote: All other car manufacturers seem to do that.

Most other car manufacturers place the battery near the engine - so the ground cable is quite short. In the case of the MGB it would mean another 6 or 7 foot run of thick copper wire. Thick copper wire is expensive - hence the decision.


1978 MGB
When diagnosing issues related to running and stalling, always check to see if you have gas in the tank first.

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Re: 1980 MGB - Recommended gauge size for battery cables
#14
ingoldsb Avatar
ingoldsb Silver Member Terry Ingoldsby
Calgary, AB, Canada   CAN
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1971 MG MGB
Quote: It wouldn’t need to be much longer than the positive cable that runs to the starter. You could connect it to one of the bolts on the bel housing.

Exactly - about 6 or 7 feet long! That is about 5 feet longer than the ground cable on a battery in the engine compartment. That was probably $5 extra!


Terry Ingoldsby
terry.ingoldsby@DCExperts.com

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